Despite a looming Brexit referendum swaying levels of transactional activity, certain law firms are enjoying a healthy pipeline of deals with Simpson Thacher & Bartlett emerging on top for global M&A deal value in Q1 2016.

According to Dealogic data, the firm worked on $101bn worth of deals at announcement, a total of 26, constituting 13% of market share. Major mandates under its belt include advising on China National Chemical Corp’s $43bn bid for Swiss seeds and pesticides group Syngenta, in what will be the largest ever acquisition by a Chinese firm; and acting on the $16.5bn merger of industrial company Johnson Controls and security provider Tyco.

While M&A rankings are notoriously hard to interpret, with US securities and secondary roles typically inflating the position of non-European law firms, such figures support the argument that US-bred advisers are steadily pushing into premium deal work in the region.

Other firms to appear in the global top ten for the first quarter included Davis Polk & Wardwell in third place with $77bn worth of deals, Jones Day in fifth with $57bn, and Freshfields Bruckhaus Deringer with $49bn worth of deals.

For European M&A lawyer rankings, US firm Davis Polk & Wardwell took the lion’s share with $59bn worth of deals, followed by Fangda Partners at $51bn, Homburger in third at $50bn, Simpson Thacher in fourth at just under $50bn. Magic Circle firms Freshfields and Allen & Overy placed seventh and ninth respectively while Weil Gotshal & Manges took the tenth spot with $12bn worth of deals.

For US M&A rankings Simpson Thacher also came top, with $51bn worth of deals, a total of 17, and marking 16% of market share. Jones Day came second with deals valuing at $47bn, a total of 81, and constituting 14% of market share. Other firms in the top ten included Weil Gotshal in third, Wachtell Lipton Rosen & Katz in fourth, and Kirkland & Ellis in fifth place.

On European activity levels, Weil Gotshal co-head of private equity Marco Compagnoni told Legal Business: ‘It started slow in the New Year and then picked up towards February and March. Activity levels have been good but are taking a lot longer to do. I can’t work out the effect of Brexit on people’s minds. When you talk to people I think they assume it’s not going to happen – but when they’re looking for reasons not to do something, it hangs in the air.’

‘There’s not much about of your classic UK buy out – there’s loads of deals being done in the Baltics or Italy – a lot of interest in privatisation and transactions involving public companies. We’re getting a lot of inquiries about that. How sustainable that will be? I don’t have a lot of visibility to feel raging confidence. Not a huge amount of activity in industrials but a lot of stuff in financial services and TMT.’